Frankfurt motor show - BMW is reviewing the necessity of car keys, says Ian Robertson, the company’s board member responsible for sales.

The fact that customers now all carry a smartphone and the availability of a BMW App which allows customers to unlock their vehicle, has made old fashioned keys less relevant, he told Reuters at the Frankfurt motor show.

BMW's smartphone app allows drivers to control various functions of the car and the ability to use a phone as verification before starting the car could replace physical keys.

“Honestly, how many people really need it,” Robertson said in an interview, explaining that customers no longer had to put the key in the ignition to make the car start.

“They never take it out of their pocket, so why do I need to carry it around?,” Robertson said, adding that the company was looking at getting rid of keys altogether.

“We are looking at whether it is feasible, and whether we can do it. Whether we do it right now or at some point in the future, remains to be seen,” Robertson said.

Many modern cars have keyless operation and a start/stop button, but these are still accompanied by an electronic key fob which drivers carry in their pockets or handbags. Many of these still have physical keys as a backup in case the fob malfunctions.

Ditching a physical key altogether could mean one less thing to carry around, but it could also leave motorists stranded if their smartphone malfunctioned, was lost or stolen, or the battery died.